Windows implementation of multiline RenderText

ui/gfx/render_text.cc

Index: ui/gfx/render_text.cc
diff --git a/ui/gfx/render_text.cc b/ui/gfx/render_text.cc
index d3c6bea6ffe682b03d68e8e071f991769e5edaa8..25eeb7772f3d24b7e91594e7b626fc9d15000843 100644
--- a/ui/gfx/render_text.cc
+++ b/ui/gfx/render_text.cc
@@ -308,6 +308,8 @@ RenderText::~RenderText() {
 
 void RenderText::SetText(const base::string16& text) {
   DCHECK(!composition_range_.IsValid());
+  if (text_ == text)
+    return;
   text_ = text;
 
   // Adjust ranged styles and colors to accommodate a new text length.
@@ -399,6 +401,7 @@ void RenderText::SetObscuredRevealIndex(int index) {
 void RenderText::SetDisplayRect(const Rect& r) {
   display_rect_ = r;
   cached_bounds_and_offset_valid_ = false;
+  lines_valid_ = false;
 }
 
 void RenderText::SetCursorPosition(size_t position) {
@@ -691,18 +694,52 @@ Rect RenderText::GetCursorBounds(const SelectionModel& caret,
     // since there is nothing to overtype.
     if ((GetTextDirection() == base::i18n::RIGHT_TO_LEFT) == (caret_pos == 0))
       x = size.width();
-  } else {
-    size_t grapheme_start = (caret_affinity == CURSOR_FORWARD) ?
-        caret_pos : IndexOfAdjacentGrapheme(caret_pos, CURSOR_BACKWARD);
-    ui::Range xspan(GetGlyphBounds(grapheme_start));
-    if (insert_mode) {
-      x = (caret_affinity == CURSOR_BACKWARD) ? xspan.end() : xspan.start();
-    } else {  // overtype mode
-      x = xspan.GetMin();
-      width = xspan.length();
+  } else {
+    size_t grapheme_start = (caret_affinity == CURSOR_FORWARD) ?
+        caret_pos : IndexOfAdjacentGrapheme(caret_pos, CURSOR_BACKWARD);
+    ui::Range xspan(GetGlyphBounds(grapheme_start));
+    if (insert_mode) {
+      x = (caret_affinity == CURSOR_BACKWARD) ? xspan.end() : xspan.start();
+    } else {  // overtype mode
+      x = xspan.GetMin();
+      width = xspan.length();
+    }
+  }
+  return Rect(ToViewPoint(Point(x, 0)), Size(width, size.height()));
+}
+
+std::vector<Rect> RenderText::RangeToViewRects(const ui::Range& x) {

[msw, 2013/07/17 06:47:18]

This function should be defined in the order it's declared in the header (move
below ToViewPoint)

[ckocagil, 2013/07/19 19:40:50]

Done.

+  std::vector<Rect> rects;
+
+  if (!multiline()) {
+    Point start(x.GetMin(), 0);
+    rects.push_back(Rect(ToViewPoint(start), Size(x.length(),

[msw, 2013/07/17 06:47:18]

nit: inline start and break the line before 'Size('

[ckocagil, 2013/07/19 19:40:50]

Done.

+                                                  GetStringSize().height())));
+    return rects;
+  }
+
+  EnsureLayout();
+
+  // Each line segments keeps its position in text coordinates. Traverse all
+  // line segments and if the segment intersects with the given range, add the
+  // view rect corresponding to the intersection to |rects|.
+  for (size_t line = 0; line < lines().size(); ++line) {
+    int line_x = 0;
+    Vector2d offset = GetLineOffset(line);
+    for (size_t i = 0; i < lines()[line].segments.size(); ++i) {
+      const internal::LineSegment* segment = lines()[line].segments[i];
+      ui::Range intersection = segment->x_pos.Intersect(x);
+      if (!intersection.is_empty()) {
+        Rect rect(line_x + intersection.start() - segment->x_pos.start(),
+                  0, intersection.length(), lines()[line].height);
+        rect += offset;
+        rects.push_back(rect);
+      }
+      line_x += segment->x_pos.length();
     }
   }
-  return Rect(ToViewPoint(Point(x, 0)), Size(width, size.height()));
+
+  return rects;
 }
 
 const Rect& RenderText::GetUpdatedCursorBounds() {
@@ -765,11 +802,13 @@ RenderText::RenderText()
       obscured_(false),
       obscured_reveal_index_(-1),
       truncate_length_(0),
+      multiline_(false),
       fade_head_(false),
       fade_tail_(false),
       background_is_transparent_(false),
       clip_to_display_rect_(true),
-      cached_bounds_and_offset_valid_(false) {
+      cached_bounds_and_offset_valid_(false),
+      lines_valid_(false) {
 }
 
 const Vector2d& RenderText::GetUpdatedDisplayOffset() {
@@ -834,30 +873,46 @@ void RenderText::UndoCompositionAndSelectionStyles() {
   composition_and_selection_styles_applied_ = false;
 }
 
-Vector2d RenderText::GetTextOffset() {
+Vector2d RenderText::GetLineOffset(int line) {
   Vector2d offset = display_rect().OffsetFromOrigin();
-  offset.Add(GetUpdatedDisplayOffset());
-  offset.Add(GetAlignmentOffset());
+  if (!multiline())
+    offset.Add(GetUpdatedDisplayOffset());
+  else
+    offset.Add(Vector2d(0, lines()[line].preceding_heights));

[msw, 2013/07/17 06:47:18]

Does this need to add a per-line horizontal offset?

[ckocagil, 2013/07/19 19:40:50]

Which horizontal offset? I don't see your point.

[msw, 2013/08/15 02:44:17]

Nevermind! The line's alignment offset is added right below this!

+  offset.Add(GetAlignmentOffset(line));
   return offset;
 }
 
 Point RenderText::ToTextPoint(const Point& point) {
-  return point - GetTextOffset();
+  return point - GetLineOffset(0);
+  // TODO(ckocagil): implement multiline.
 }
 
 Point RenderText::ToViewPoint(const Point& point) {
-  return point + GetTextOffset();
+  if (!multiline())
+    return point + GetLineOffset(0);
+
+  // TODO(ckocagil): refactor this to traverse all line segments to support rtl.
+  DCHECK(lines_valid_);
+  int x = point.x();
+  unsigned int line = 0;
+  while (line < lines_.size() && x > lines()[line].width) {
+    x -= lines()[line].width;
+    ++line;
+  }
+  return Point(x, point.y()) + GetLineOffset(line);
 }
 
-Vector2d RenderText::GetAlignmentOffset() {
+Vector2d RenderText::GetAlignmentOffset(int line) {
+  int width = lines()[line].width;

[msw, 2013/07/17 06:47:18]

nit: make this const, maybe DCHECK lines_ validity.

[ckocagil, 2013/07/19 19:40:50]

Done.

   Vector2d offset;
   if (horizontal_alignment_ != ALIGN_LEFT) {
-    offset.set_x(display_rect().width() - GetContentWidth());
+    offset.set_x(display_rect().width() - width);
     if (horizontal_alignment_ == ALIGN_CENTER)
       offset.set_x(offset.x() / 2);
   }
   if (vertical_alignment_ != ALIGN_TOP) {
-    offset.set_y(display_rect().height() - GetStringSize().height());
+    offset.set_y(display_rect().height() - GetMultilineTextSize().height());
     if (vertical_alignment_ == ALIGN_VCENTER)
       offset.set_y(offset.y() / 2);
   }
@@ -865,14 +920,13 @@ Vector2d RenderText::GetAlignmentOffset() {
 }
 
 void RenderText::ApplyFadeEffects(internal::SkiaTextRenderer* renderer) {
-  if (!fade_head() && !fade_tail())
+  if (multiline() || !fade_head() && !fade_tail())
     return;
 
-  const int text_width = GetStringSize().width();
   const int display_width = display_rect().width();
 
   // If the text fits as-is, no need to fade.
-  if (text_width <= display_width)
+  if (GetStringSize().width() <= display_width)
     return;
 
   int gradient_width = CalculateFadeGradientWidth(GetFont(), display_width);
@@ -903,7 +957,7 @@ void RenderText::ApplyFadeEffects(internal::SkiaTextRenderer* renderer) {
   }
 
   Rect text_rect = display_rect();
-  text_rect.Inset(GetAlignmentOffset().x(), 0, 0, 0);
+  text_rect.Inset(GetAlignmentOffset(0).x(), 0, 0, 0);
 
   // TODO(msw): Use the actual text colors corresponding to each faded part.
   skia::RefPtr<SkShader> shader = CreateFadeShader(
@@ -967,12 +1021,23 @@ void RenderText::UpdateLayoutText() {
     iter.setIndex32(truncate_length_ - 1);
     layout_text_.assign(text.substr(0, iter.getIndex()) + ui::kEllipsisUTF16);
   }
+
+  line_breaks_.clear();
+  base::i18n::BreakIterator iter(GetLayoutText(),
+                                 base::i18n::BreakIterator::BREAK_LINE);
+  bool success = iter.Init();
+  CHECK(success);
+  do {
+    line_breaks_.push_back(iter.pos());
+  } while (iter.Advance());
 }
 
 void RenderText::UpdateCachedBoundsAndOffset() {
   if (cached_bounds_and_offset_valid_)
     return;
 
+  // TODO(ckocagil): Add vertical offset support for scrolling multi-line text.
+
   // First, set the valid flag true to calculate the current cursor bounds using
   // the stale |display_offset_|. Applying |delta_offset| at the end of this
   // function will set |cursor_bounds_| and |display_offset_| to correct values.